Fuse holder



Aug. 11, 1953 c. w. HEATH FUSE HOLDER Filed Feb. 5, 1952 Maze-N702 c. W H54 76 A T raausy Patented Aug. 11, 1 953 'FUSTE HOLDER Clarence Willans He casb l signor to Cinch Manufacturing En n as- Corporation,

Chicago, 111., a corporation of Illinois Application February 5, 1952,

Serial No. 269,969

In Great Britain February 26, 195i 1 Claim. (01. 2 1 28) This invention relates to fuse holders of the kind comprising a body portion of insulating material having a, bore to receive a cartridge type fuse, which is retained by a cap or the like detachably secured to the body to close the open end of the bore, the opposite ends of the inserted fuse being adapted to engage electrical contacts in the bore and cap.

It is an object of the invention to provide an improved form of fuse holder having means for ensuring that the fuse cartridge is isolated from the electrical terminals of the holder when the cap is removed.

According to the present invention a fuse holder of the kind referred to includes a reciprocably mounted contact for engaging the fuse cartridge adapted to be mounted in the holder, spring means being provided tending to urge the said contact to a position wherein it is isolated from an electrical terminal which is adapted to be connected with an external electrical circuit.

The invention also includes a fuse holder of the kind referred to wherein an electrical contact for engaging the fuse cartridge in the bore of the holder comprises a member which is displace ably mounted within the bore and is normally urged by spring means away from an electrical terminal at the inner end of the bore, the arrang'ement being such that when the fuse cartridge is retained in the bore by assembly of the detachable cap or the like the said member is forced inwardly of the bore against the action of the spring so as to engage the said electrical terminal at the inner end of the bore, but when the cap is removed the spring displaces the member outwardly away from the said terminal. As the outer end of the fuse is engaged by the contact in the cap which is in electrical engagement with a second terminal, the inserted fuse bridges the terminals which are adapted to be connected in the external electrical circuit which is to be protected by the fuse.

On the cap being removed however, the reciprocably mounted contact is forced outwardly of the bore away from the circuit terminal, by its spring, so that the cartridge is isolated from the electrical circuit terminal and is accordingly dead.

To enable the invention to be fully understood it will now be described with reference to the accompanying drawing, in which:

Fig. 1 is a sectional elevation of a fuse holder according to one embodiment of the invention;

Fig. 2 is a sectional elevation of the holder with the fuse and end cap removed, and

Fig. -3 is an end view looking into the open end of the bore of the holder.

As shown in the accompanying drawing-the fuse holder comprises a generally cylindrical body I of insulating material formed with an axial bore 2. An electrical terminal is mounted g the inner end of the bore, this terminal comprisinga split metal sleeve 3 hav- 4 projecting through an aperture of the bodyfor connection with one terminal of an electrical circuit. The split sleeve 3 extends in axial alignment I with the bore and is s ecured inposition by providing the behind the base of the body adjacent to the aperture 5 through which the tail piece extends. W

I'he contact 2 to i i bi 1 isi' ib n e the d permit it being reciprocated and comprises a tubular portion having a diameter adapted to make a sliding fit intothesplit {sleet/e 3, the contact "I is mountedonadisc 8 of insulating material which has a diameter slightly less than the bore; 2 so as to be freely slidable therein. A coil spring 9 is interposed between the inner end of the bore and the disc 8 so as to urge the latter and the contact lou'twardly of the bore away from the split sleeve}. The coil spring surrounds the tubular portion of the contact I but the spring does not provide an electrical path between the contact I and split sleeve 3, and the parts are accordingly electrically isolated when not actually engaging.

The reciprocable contact 1 is retained against complete removal from the bore by an apertured washer ID of insulating material which is located in the bore adjacent the open end thereof and is secured by means to be described.

A metal sleeve is fitted into the open end of the bore and comprises a split tubular portion H closely fitting the inner diameter of the bore and formed with bayonet joint slots I2. The inner end of the sleeve is provided with axially extending lugs I3 which project through slots in the side wall of the body I to the outer surface thereof, the lugs having resilient tongues l4 adapted to snap past the end walls of the slots when the sleeve is inserted into the bore and thereby automatically securing it in position. The lugs [3 are also adapted to engage flats on the periphery of the washer l0 and thereby hold it on a shoulder formed in the bore. One of the said lugs I3 is adapted to serve as a second external terminal of the fuse holder for wiring to the external circuit to be protected by the fuse.

A cap is provided for closing the open end of the body I and comprises a base of resilient insulating material such as polythene having a recess on its inner face in which is mounted a metal sleeve [6 having an end portion I! and outwardly projecting lugs l8 on its outer end adapted to co-operate with the bayonet joint slots l2. The base I5 of the cap may be formed with one or more inwardly extending projections or dimples 19 adapted to spring into holes in the sleeve to secure the latter in place. The resilient nature of the material of the cap permits its wall to be flexed sufficiently for the tight fitting sleeve to be inserted past the dimples, which spring back into the holes in the latter when in alignment.

In use a fuse cartridge F is inserted into the axial bore 2 in the body of the holder, its lower end extending through the aperture in the washer I0 and resting on the adjacent end portion of the reciprocably mounted contact I. When the cap is removed as shown in Fig. 2 the contact 1 is held away from the end terminal 3 by the spring 9 and accordingly there is no risk of the fuse touching a live terminal while it is being handled. The outer end of the fuse cartridge F is held out of contact with the sleeve II by the insulating washer lfi in which it is supported. The cap is assembled by inserting the sleeve 16 into the bore 2 and engaging the lugs IS in the bayonet slots l2 in the sleeve H in the body I. The outer end of the fuse cartridge abuts the end portion I! of the cap sleeve l6 so that when the cap is forced inwardly of the bore the cartridge is forced into the bore against the action of the spring 9 until the inner end of the contact I is forced into the tubular terminal 3 at the base of the bore to make efficient electrical engagement therewith. The cap is secured by a part turn to engage the lugs 18 in the locking portion of the bayonet slots.

It will be understood that when the cap is fully assembled the cap sleeve [6 which engages one end of the cartridge F is electrically connected by lugs 18 with the sleeve l I and the latter is adapted to be connected with an external electrical circuit through the lugs I3 which project to the outer side of the holder.

The terminal 4 at the base of the holder is in electrical engagement with the inner end of the fuse cartridge through the split sleeve 3 and contact I and the terminal 4 is adapted to be connected with another wire lead of the external electrical circuit to be protected by the fuse.

The fuse holder is particularly adapted for mounting on a panel such as, for example, that of a wireless set or other form of electrical apparatus and the body of the holder is preferably provided with a peripherial radial flange 20 adjacent to the open end of the bore and part of the body is screw threaded as at 2 l. The holder is assembled with a panel by inserting it through an aperture in the panel until the flange 20 abuts one face thereof and is secured by screwing the nut 22 on to the threaded portion 2| to abut the opposite face of the panel.

I claim:

A fuse assembly providing a holder of insulating material having a bore, a terminal member at one end of said holder, a contact member displaceably mounted Within said bore, spring means in said bore normally urging said contact member away from said terminal member, a metal sleeve disposed in the bore of said holder adjacent to the end thereof away from said terminal member, said sleeve and holder having cooperating snap fastener means whereby said sleeve may be automatically attached to said holder, said sleeve having an integral wiring terminal, a detachable cap at the end of said holder having said sleeve, said cap having a metal cup-shaped element, said cup-shaped element having means for electrical engagement with the outer end of a fuse cartridge which cartridge is adapted to make electrical connection with said contact member when said cap is attached to said holder, and said cup-shaped member having means for fastener engagement with said sleeve to connect electrically said cap and sleeve and to hold said cap in removable assembly with said holder.

CLARENCE WILLANS HEATH.

References Cited in the file of this patent UNITED STATES PATENTS Number 

